The human body is a complex structure of biological mechanisms that require various nutritional components to function. These nutrients are classified as macronutrients, (proteins, carbohydrates, fats, fibre and water), micronutrients (vitamins, minerals and trace elements) and phytochemicals.


Vitamins are essential nutrients that are needed to ensure metabolic reactions are carried out properly. When the body lacks vitamins, reactions can malfunction which eventually leads to various health issues. Most of these important vitamins can’t be made in the body, meaning they must be consumed in your diet. There are 13 vitamins, which fall into two separate groups:

  • Fat-soluble vitamins: A, D, E and K
  • Water-soluble vitamins: B6, B12, C and the B vitamins (folate, thiamine, riboflavin, niacin, pantothenic acid and biotin)

Fat-soluble vitamins are needed for many bodily functions, including correct vision and bone growth, the absorption of calcium, use as antioxidants and the development of clotting factors. Fat-soluble vitamins are found in brightly coloured fruits and vegetables (such as carrots, broccoli, kiwi, spinach and cantaloupe), fish (such as canned tuna, salmon and sardines), sunflower seeds/oil, milk and nuts.

Water-soluble vitamins complete a myriad of different functions, including the metabolising of carbohydrates and protein, use as an antioxidant, and being needed for neuro-transmitter function. Water-soluble vitamins are found in yeast, liver, dairy, whole grain and citrus fruits.

Because different vitamins are required in different amounts, it can be difficult knowing which vitamins are lacking in your diet. For this reason it’s much easier to consume an array of vitamin-dense foods.

Dietary elements and trace elements

Dietary elements are metallic and non-metallic elements that are needed in the body. Those needed in minute quantities are known as trace elements. Dietary elements have various functions – some have structural jobs (phosphate, calcium and magnesium) whereas others act as antioxidants (selenium, manganese and zinc.)

Mineral deficiencies can be caused by poor diets, usually those high in junk food and low in fruits and vegetables. Diets comprised of high-fibre, fruit, nuts, vegetables, lean meats, oily fish and whole grains contain all of the elements needed for healthy functioning. Mineral supplements are also used to treat specific deficiencies.

Calcium – Role of Calcium in the Body and Food Sources

What does calcium do?

  • Helps blood to clot
  • Helps muscles and nerves function properly
  • Makes your teeth and bones strong

Food sources of calcium

  • Oysters
  • Legumes
  • Milk
  • Dark green vegetables
  • Sardines
  • Almonds

Folic Acid – Role of Folic Acid in the Body and Food Sources

What does folic acid do?

  • Helps the body produce and maintain new cells
  • Helps prevent changes to DNA (i.e. cancer)
  • Prevents nervous system problems which can cause birth defects

Food sources of folic acid

  • Dark green leafy vegetables
  • Oranges and other citrus fruit
  • Avocado
  • Seeds and nuts
  • Beans
  • Peas

Iron – Role of Iron in the Body and Food Sources

What does iron do?

  • Helps transport oxygen around the body
  • Used to make red blood cells

Food sources of iron

  • Meat
  • Whole grains
  • Dark green vegetables
  • Legumes
  • Seeds and nuts
  • Dried fruit

Potassium – Role of Potassium in the Body and Food Sources

What does potassium do?

  • Helps nerves function properly
  • Helps keep the heart beating at a regular rhythm
  • Maintains a normal water balance between cells and body fluids

Food sources of potassium

  • Cereal
  • Bananas
  • Tomatoes
  • Oranges
  • Potatoes

Sodium – Role of Sodium in the Body and Food Sources

What does sodium do?

  • Maintains blood pressure
  • Helps maintain a normal fluid balance in the body
  • Involved in transmission of nerve signals

Food sources of sodium

  • Bread
  • Table salt
  • Most other foods

Vitamin A: Retinal – Role of Vitamin A in the Body and Food Sources

What does vitamin A: retinal do?

  • Important for good vision, healthy skin and healthy hair
  • Helps the heart, kidneys, lungs and other organs function properly

Food sources of vitamin A: retinal

  • Meat
  • Eggs
  • Spinach
  • Kale
  • Red-orange vegetables that contain carotene (carrots, sweet potato etc.)

Vitamin B1: Thiamin – Role of Vitamin B1 in the Body and Food Sources

What does vitamin B1: thiamin do?

  • Helps prevent a disease called beriberi
  • Used to release energy from food

Food sources of vitamin B1: thiamin

  • Meat
  • Whole grains
  • Peanuts
  • Peas
  • Seeds and nuts
  • Dried beans

Vitamin B12: Cobalamine – Role of Vitamin B12 in the Body and Food Sources

What does vitamin B12: cobalamine do?

  • Helps make DNA
  • Helps the nervous system grow and develop

Food sources of vitamin B12: cobalamine

  • Meat
  • Milk
  • Fortified cereals
  • Eggs

Vitamin B2: Riboflavin – Role of Vitamin B2 in the Body and Food Sources

What does vitamin B2: riboflavin do?

  • Used to build and maintain body tissues
  • Helps convert food into energy

Food sources of vitamin B2: riboflavin

  • Meat
  • Whole grains
  • Mushrooms
  • Green and yellow vegetables

Vitamin B6: Pyridoxine – Role of Vitamin B6 in the Body and Food Sources

What does vitamin B6: pyridoxine do?

  • Helps the body make several neurotransmitters
  • Helps convert food into energy

Food sources of vitamin B6: pyridoxine

  • Rice
  • Fish
  • Nuts
  • Potatoes
  • Bananas
  • Chickpeas

Vitamin C: Ascorbic acid – Role of Vitamin C in the Body and Food Sources

What does vitamin C: ascorbic acid do?

  • Works as an antioxidant
  • Helps build strong bones, teeth and gums

Food sources of vitamin C: ascorbic acid

  • Oranges and other citrus fruits
  • Berries
  • Peppers
  • Cabbage
  • Kale

Vitamin D – Role of Vitamin D in the Body and Food Sources

What does vitamin D do?

  • Helps prevent rickets
  • Promotes the growth of strong bones and teeth

Food sources of vitamin D

  • Fatty fish
  • Egg yolks
  • Cheese
  • Mushrooms

Vitamin E – Role of Vitamin E in the Body and Food Sources

What does vitamin E do?

  • Helps the process of blood production
  • Prevents cell membranes from being damaged
  • Protects vitamin A

Food sources of vitamin E

  • Vegetable oil
  • Spinach
  • Sweet potato
  • Avocado
  • Seeds and nuts

Vitamin K – Role of Vitamin K in the Body and Food Sources

What does vitamin K do?

  • Helps blood to clot
  • Helps build strong bones

Food sources of vitamin K

  • Green leafy vegetables
  • Cucumber

Zinc – Role of Zinc in the Body and Food Sources

What does zinc do?

  • Forms enzymes
  • Helps heal wounds
  • Helps transport carbon dioxide round the body

Food sources of zinc

  • Oysters
  • Legumes
  • Milk
  • Whole grains
  • Meat

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